A thermal recording apparatus is, as shown in FIG. 1, generally composed of a thermal recording head 1, a driver 2 and a control circuit 3. The thermal recording head 1 is constituted by a multiplicity of heating elements which are disposed in parallel. The driver 2 is constituted by a multiplicity of driver circuits adapted to drive the respective heating element blocks of the thermal recording head 2 in response to recording signals. The control circuit 3 is adapted to distribute recording signals to the driver circuits in accordance with a recording procedure and to control driving conditions. An apparatus, such as a facsimile machine, which is required to drive a multiplicity of heating elements employs the heating element portion and the driver circuits as one integrated block. In recent thermal recording apparatus in particular, a device in which heating elements are disposed in parallel is prepared by employing a thin- or thick-film printing technique. It is also common to form the driver circuits into an IC in which the driver circuits are mounted on the same substrate.
A thermal recording apparatus of this type is disclosed, for example, in the specification of Japanese Patent Laid-Open No. 44584/1983 "Control Circuit for Matrix Recording" laid open in Japan on Mar. 15, 1983 and shown in the accompanying drawings FIGS. 1 and 2.
The above-described prior art, however, involves a limited data transfer speed, which disadvantageously makes it difficult to realize an apparatus having an improved operation performance. Further, the control circuit 3 and the driver 2 internally handle recording data, bit-by-bit, in parallel, but to effect data transfer it is necessary for the control circuit 3 to incorporate a parallel-to-serial conversion circuit and for the driver 2 to incorporate a serial-to-parallel conversion circuit, which fact disadvantageously involves a large number of required circuit elements.